Flame propagation analyzer



Aug- 25, 1936. A. E. KROGH 2,052,181

FLAME PROPAGAT ION ANALYZER ATTO @ZZ wim Aug. 25, 1936.` Al E KROGH 2,052,181

FLAME PROPAGATION ANALYZER Filed Aug. 6, 1930 2 Sheets-Sheet 2 /A/VE/vroe `Patentet'l ug. 25, 1936 Unirse srs'rss PATENT orrics z,o`52,1s1- um rnorsoa'rron ANsLrzEn Anker E. Krogh, Philadelphia, Pa., assig'nor to Y' Y The Brown Instrument Company, Philadel- *Y Y pliia, Pa., a corporation of Pennsylvania Application August 6,

. 5 Claims. This invention relates to combustible materials such as fuels and especially fuels of a vaporous or gaseous nature. This invention relates to the determination of the heating eiect of' fuels and also to the preparation of fuels of a constant heating value.

Heretofore to measure continuously thevheating value of a. gas it has been customary to measure the effect of the combustion of a given quantity of the heating duid upon the tempera` 'ture of another duid such as air or water. Such procedure is very complicated and is subject to very large errors due to flow changes in the heating or in the heated uid, etc.. as is `well known in the art.

Due to these complications operators have frequently been compelled to estimate the heating value of a fuel by observing a name and its structure. This procedure is very largely affected by sunlight or artificial light and cannot be accomplished within close limits.

It is the object of this invention to provide an improved means for measuring the heating effect of combustible iiuids. It is another object of this invention to provide an improved means for measuring the characteristics of a flame and particularly the temperature gradient ofl a stationary name.

'Ihe features of novelty which characterize the present invention are pointed out with particularity in the claims appended to and forming a part of this specication. For a better understanding of the invention and its advantages, however. reference should be had to the following detailed description taken in connection with the accompanying drawings, in which Fig. l shows, in an elevation and partly in section, the name analyzing device of this invention.

Fig. 2 shows, in elevation partly broken. away and in section, another view of the ame analyzing device of this invention.

According to this invention the heating edect .or value oi' the combustible material 'is ascertained by burning some of the fuel and determining the characteristics of the ame produced. The stationary type of flame is used as the form inwhich the name characteristics may bemost practicably and accurately determined. Accordingly a burner is provided which will burn the combustible material with a stationary ame of well dened structure and characteristics. Such a burner is shown in Fig. 1.

The combustible material. usually a gas or a vapor, "enters through pipe connection I t.; xed in the block ii-oi the burner. Block II is pro- 1930, Serial No. 473,501

(Cl. Til-32) vided with a passage or orifice I2 of small size, through which the combustible fluid passes. A tube I3 is arranged to receive the combustible Vfluid passing through the orifice I2, and the tube i3 is supported relative to the block ii by the cylinder It fixed to the block II by any suitable means such as the screw i5. The tube iii may be conveniently supported in the cylinder it by rings iii. The cylinder Iii is provided with openings il. which permit the passage of air or any lo other uid surrounding the burner therethrough. The tube I3 is provided with a sleeve or collar IB adjustable longitudinally thereof. The longitudinal adjustment of the sleeve or collar it relative to the tube I3, may be eected in any 15 of a variety of ways, and preferably is made so adjustable by providing the tube and the collar with screw threads. The sleeve or collar is is provided with a substantially at surface on its bottom face I9. By adjusting the sleeve or collar it longitudinally of the tube It, a gap between the block il and the collar It may be varied so asta vary the rate at which air is drawn in the tube I3 by the aspirating edect of the combustible material flowing from the erice 25 i2 into the tube I3.

The collar I8 conveniently carries a Vsprocket 2@ driven by a chain 2i trained over the sprocket 22. The sprocket 22 is fixed on shaft it, rotatable in bearings 2t. The shaft 23 carries a gear 30 25 meshing with gear 2b rotatably carried by support 2l. The shaft 2d, upon which the gear -26 is fixed. is provided with a kerf with which a suitable tool may be engaged for acuusting the position of the collar or sleeve It. l 35 A frame 29 is carried by the burner and is conveniently supported on the tube It by a collar tu fixed on the tube and supporting the bar ti which is split and provided with an opening tting around the sleeve 30. the bar 3i being clamped 40 onto the sleeve 3i! by screws 32, drawing together its split halves. At either end oi the ber 3i and clamped between its split halves are upright standards 33 which are heldin ilxed spaced rela tion at their upper ends by the ring tt, bolted to 45 the uprights 33 by bolts 35-35. The ring td serves to maintain the vertical standards $3 in eccurately spaced relation without interfering with the ilame of the combustible gas issuing from the burner. The upright standards Si carry thermo- 5G couples t6 of any suitable material. preferably of platinum and platinum-rhodium. The thermocouples are fixed in the standards Se in any suitable manner and preferably by clamping them in place. The junction of the thermo-couples extend y inlet pipe I0. A plug 43 is threaded'into the block into the body 31 of the fiame of combustible gases issuing from the burner.

The thermo-couples 36-36 are connected differentially, that is the polarities of some of the thermocouples are opposed to the polarities of the remaining thermocouples as shown in Fig. 1, to an indicating, recording, or controlling instrument '38 vof any suitable and well known type.

In order to protect the thermo-couples from mechanical injury, especially when the combustible gases are being lighted, a screen 39 surrounds the support in such a position, as shown in Fig. 1, as to protect the thermo-couple 36. 'I'he screen 39 depends from ring 40 to which it is secured by brazing, soldering, Welding or clamping, or any suitable manner. The ring 40 is secured to the standards by bolts 35. The screen 39 isprovided with alower band 4I which symmetrically weights the screen so that the screen will hang in a position as shown in Fig. 1 when the instrument is upright. In addition, the band 4I cooperates Jwith bar 3l to support the screen 39 at its lower marginV when the burner is not in upright position.

The block I I has a passage 42 leading from the II and is provided with a passage 44 of restricted size., leading to the passage 42 in the block II. A tube 45 extends from the plug-43 and is open to the passage 44. 'I'he tube 45 is open at its upper end 46 and acts as a pilot light for the burner. The relative size of the orifices I2` and 44 is such that only a small percentage of the combustible fluid entering through pipe connection I passes into the pilot tube 45.

In the operation of the device as so far described, the combustible fluid entering through the pipe connection I0, passes through the orifice I2 into the tube I3 land draws, by an aspirating action, a supply of primary air through the gap between sleeve I8 and the block II. The supply of primary air can be adjusted to any desired quantity by adjusting the gap between the sleeve I8 and the block I I. The mixture of combustible gas and air is lighted as it issues from the tube I3 and burns with Va stationary flame composed of the body part 31 and inner cone 41. The size of the name is determined by the supply of primar'y air and by the quantity and composition of the combustible fluid. As the quantity or the quality of the combustible fiuid varies, the inner cone 41 rises and falls, and the temperature gradient or temperature difference between those parts of the ame in which junctions of' the 36 positioned in the body 31 of the flame and so positioned that none of the thermo-couples* will enter into the cone 41 in any position or size of the flame. It has been found by experiment that as the structure of the flame changes so that the height of the inner cone 41 varies, the temperature gradient between those parts of the flame in which the junctions vof the thermo-couples are positioned, varies in exact proportion to the height of the inner cone ofthe ame. It has long been recognized that the height of the inner. cone of the flame is a practical working standard for the heating effect of a ame of burning gas having unvarying constituents. Accordingly the variation of the temperature gradient along the flame, in the direction of flame propagation, is a practical measure of the heating effect of the rarwhich is responsive to the variation in the temy perature gradient in the name, may be employed to indicate or record the heating value or eiect of the combustible fluid, or it may be employed to control a system so as to adjust the system in accordance with the variation in the heating effect of a flame of the combustible fluid being used in the system.

In addition to the well known fact that from a practical operating standpoint the height of the inner cone of the flame of the type produced by the burner shown in Fig. 1, is regarded as a satisfactory criterion of the heating value of a fluid containing non-varying constituents, it has been determined experimentally that the height of the inner cone 41 does bear a definite relation to the heating value of a combustible uid so long as the nature of the constituents of the combustible fiuid does not change. Variations in the proportions of the constituents of the combustible temperature gradient of the fiame measured by` the thermo-couples 36 is in exact proportion to the height of cone 41, 'the temperature gradient in the flame may be used through the instrumentality of the control device 33 to eiect automatic control of the composition of a combustible mixture so as to maintain it of a constant heating value or eiect. .f

While it has been found entirely satisfactory to feed the primary air to the burnerthrough a gap such as that between the sleeve I3 and the block II in the construction shown in Fig. 1, as an alternative construction it may be desirable and practicable to feed the primary air into the burner tube from a supply of compressed air through suitable pressure controlling device. Where it is desired to use oxygen or to precondition the primary air, a supply of air such as an auxiliary supply connected to the pressure tube by tubing may be used.

In addition. as another alternative way in which the flame analyzer may be used, air or oxygen may be fed through the burner tube and the gas under test may be used as the atmosphere surrounding the burner tube.

As shown in Fig. 1, four thermo-couples are used in two pairs symmetricallyarranged about the axis of the flame so that deviations in-the ame shape from a symmetrical shape will not 'effect the operation of the-instrument. In the sired, a larger number of thermo-couples may be used to determine'-the temperature at a series oi' points in the fiame and thereby measure more accurately the temperature gradient throughout vthe body of the flame.

In order to make the burner and its associated parts an instrument of a high degree of accuracy, it is found convenient to surround the burner with 45 i burner dies out, the pilot 4B will continue to burn a shield such as shown in Fig. 2. which is of the v following construction:

A' base I8 has attached thereto the standards '49, which support a cup shaped sheet metal mem- 1 ber 50. The member 59 is provided with an aperture 5i in its base through which the pipe connection I0 passes. At its top, member 50 is provided with an aperture 52 into which the cup shaped member 53 nts. 'I'he cup shaped member 53 is provided with an aperture 5I through which pipe connection i0 passes and a bushing 55 is provided for separating the'members 50 and 63. 'I'he block Ii rests upon the bottom of the cup shaped member 63, which thereby supports the burner. A tubularmember 56 rests in a flange 51 of the member 53 and supports at its topthe cap 58 provided with the flange 59, which flts on to the upper end of the cylinder, The members Ml and 53 are provided with apertures 60 through which air may be drawn into the interior of the casing to provide a steady supply of air for the burner. 'I'he products of combustion pass upwardly through the opening BI and out through openings 82 in cap 58. The cap 58 is provided with a baille 63 depending therefrom, which serves to prevent the flame from striking the casstructed and the apertures are such that the flow of air to the burner and of the products of combustion from the burner are not appreciably hindered. I

In case the combustible content of the combustible mixture falls so low thatthe flame of the for a considerable length of time due to'the fact that the combustible gases issuing from it are not mixed with a primary supply of air, and accordingly when the composition of the gas under test again changes to a combustible mixture, it will be lighted by thevpilot flame.

Inasmuch as it is desired to employ the flame analyzer to respond to changes in the combustible condition of the combustible mixture or its heating eilect, it'is desirable that the combustible mixture be fed to the burner at a constant rate and under constant pressure, and it may be desirable to precondition the combustible gas as to moisture content andV temperature. .Accordingly the flow of gas under test may be controlled by any suitable pressure regulator, either of wet or dry type, and the gas may be brought to and held at an even temperature, and the moisture content may be adjusted by any of the weil known and suitable devices available.

An orifice db is conveniently provided in the pipe line 85 leading to the burner for creating 'a pressure differential depending on the rate of ow which is measured by U tube manometer Bl. In addition a U tube pressure gauge iid may be attached to the pipe line 6B to measure the pressure of a combustible mixture flowing to the burner.

In the operation of many systems for supplying gas for heating and industrial purposes, the available supply of gas changes from time to time and accordingly the combustible mixture may be made up of a mixture of natural gas. producer gas, coal gas, butane, hydrogen, and many other inflammable fluids; the quantities of such gases which are available, varying from time to time in a manner uncontrollable by the user. In maintaining a supply of fuel for home and industrial consumption 'where the mixture must be made up from such a variable supply of the constituents of the mixture. it is necessary to adjust the composition of the mixture from time to time as the supply of the constituents of the mixture varies, in order to keep the heating effect and the flame produced by burning the gas substantially constant. The flame analyzer herein Vdisclosed lends itself readily to the control of a system for maintaining a mixture of gases at a substantially constant heating edect or flame structure.

In addition, the flame analyzer may be used for other purposes than to adjust the composition of a combustible mixture of gases in a predetermined manner; for example, where a combustible mixture is employed for heating a particular material or product, variations in the heating effect of the combustible mixture as determined by the flame analyzer may be caused to control the rate of flow of the medium being heated, or may be caused to control any of the many furnace conditions such as damper position, draft position, etc., to adjust the resulting effect upon the material being heated in the manner desired.

While a particular embodiment of the flame analyzer has been herein disclosed by way of illustration, itis not intended so to limit the invention, inasmuch as many modifications in the details of construction and operation of the instrument and the control 'systems in which it may be used, may be made, as will be apparent to one skilled in the art, without departing from the scope and spirit of the invention.

Having disclosed my invention, what I claim is:

l. The combination with means for burning fluid fuel in an elongated stationary flame, of means for measuring a temperature gradient in said flame comprising a plurality of temperature responsive devices distributed longitudinally of the flame and extending into the flame at one side of the latter and another plurality of temperature responsive devices extending into the flame at the opposite side of the latter and also distributed longitudinally of the name, the devices at the one side producing one eiect, and the devices at the other side producing another effect which decreases or increases relatively to said one edect accordingly as the axis of the flame is displaced toward or away from said one side, and means 'responsive to the sum of said effects.

2. A device for measuring the heating effect of a combustible fluid which consists of means for burning a sample of the fluid as a stationary flame in which the combustion progresses from an -initial surface of combustion, first means responsive to the temperature difference between a plurality of parts of theiiame distributed along the direction in which 'combustion progressesp second means spaced apart from the said first means in a direction transversely of the direction in which combustion progresses and responsive to the temperature difference between a plurality of parts of the flame distributed along the direction in which .combustion progresses, and measuring means jointly responsive to said first and second means, whereby onA deection of the ilame toward either of said means and away from the other of said means the increased response of one means neutralizes the effect of the decrease in the response of the other means. A

3. A device for measuring the heating effect of a combustible iiuid which comprises, a. burner for burning the iiuid as a stationary flame. a support fixed relative to the burner, rst temperature responsive means comprising a plurality of tema perature responsive elements held in the am by the support. said elements being arranged along the direction of ilame propagation, second temperature responsive meansA displaced transversely of and producing an effect in the same direction as the iirst mentioned means and comprising a plurality of temperature responsive elements arranged' along the direction of ame propagation and an indicator connected to said elements so as to respond to the sum of the effects of the first and second means.

4. A device comprising a burner for burning a `iluid as a stationary flame, a. support, a plurality of thermo responsive elements mounted on said support and adapted to project into said flame when burned to produce an effect responsively to the flame temperature, means responsive to the combined effects of said elements, the said elements being displaced angularly about the axis of said burner, and arranged so that the individual effects of the elements displaced angularly from one another are in the same direction, whereby movement of the ilame. in a direction transversely .of said axis, will be substantially ineiective upon the means responsive to the combined eiect of said elements. q

5. The combination with means for. burning uid fuel-in an elongated stationary flame, ofy

means for measuring a temperature gradient in said flame comprising a plurality of fixed thermocouple junctions in said ame, distributed longitudinally thereof on opposite sides of the iiame and at least one pair of said thermocouples being arranged in the same horizontal plane at opposite sides o the flame, the polarites of the 20 thermocouples being such that the thermocouples disposed on the same side of the flame are diiferentially connected and the thermocouples in the sameI horizontal plane are additiv'ely connected. f

ANKER E. KROGH. 

